Pencil Anode Broke Off

[JC766]

I know what a zinc anode does, but I can't clearly determine if it must be in contact with the metal or if being suspended in solution would do the trick as well. First off freshwater boat only. I bought a pair of SS aftermarket manifolds. They use a pencil anode and one has broken off inside and I cant get it out. Would it still work floating around in their or does it have to be touching the manifold. In addition if it must touch the metal its protecting, then why is it inserted into a brass plug? The 3/8 pencil anode screws into a brass plug that screws into the stainless steel manifold.

 

[sub2010ss]

Im still learning about pleasure boats, but here is what I know from the Navy.

Galvanic corrosion is an electrochemical process in which one metal corrodes preferentially to another when both metals are in electrical contact, in the presence of an electrolyte.

The sacrificial anode, ie zinc, must also be in contact with one of the metals.

 

[Scott Danforth]

galvanic corrosion is electrical in nature. the brass is electrically conductive. it is also brass because a stainless plug in a stainless manifold will only go in once, gall the threads, and never come back out. Brass will come back out as it is a bearing material, and it is harder than your stainless, so it wont gall.

 

[Watermann]

I would wonder about a 3/8" piece of zinc wandering about inside my manifold, I don't know if it could go up the riser and out the elbow to jam in the flappers or not but it could or plug a passageway.

 

[GA_Boater]

Since you are dealing with a sacrificial anode, they are made to be replaced. So get a new one. The one floating around isn't going to do any corrosion prevention and could cause more expensive damge when it decides to exit.